Many techniques to change emphasis of feeling of material (especially, “apparent gloss” and “apparent shininess”) of an object in an image by image processing are proposed. As to a first method of conventional technique, a model to link “sensitivity amount of high order” (such as a feeling of metallic material) with the image is trained, and the feeling of material is changed using the model trained. As to a second method of conventional technique, the image is separated into a diffused reflection image (color of the object itself) and a specular reflection image (color reflected from the object by illumination light). By adding the specular reflection image emphasized to the diffuse reflection image, an apparent gloss of the object in the image is emphasized.
However, in above-mentioned two methods, many computer resources are necessary to change the apparent gloss.